Effect of pH on Photosynthesis in native cyanobacterium Fischerella sp.
2020
Shokravi, Shadman | soltani, neda
Stigonomatalean cyanobacterium Fischerella sp. is one of the few native strains in Iran that has relatively enough information about the operation of its photosynthetic machinery in different conditions of acidity and alkalinity. This information is the result of studies conducted from 2004 to the present. In this article, the most important results related to these articles are considered. The results show that this cyanobacterium is alkaliphile. Under alkaline condition (pH 9) and limited light intensities (2 micromoles of quanta per square meter per second), the highest rate of oxygen liberation is observed. Under these conditions, alpha and Ik reach their highest and lowest levels. Photoinhibition is not observed up to a light intensity of 1400 μmol quanta per square meter per second. Light-harvesting complexes are fully structured in both the phycobilisome and carotenoids. The activity of photosystems, especially photosystem two, reaches its maximum. The ratio of photosystem two to one is at the highest. The transition from these condition to acidic causes a significant reduction in all of these characters. Transition to extreme alkaline conditions (pH 11) at salinity higher and lower than 80 mM causes damage to the photosynthetic apparatus, oxygen liberation, and reduction of the photosystems ratio.
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